Kinetica is a computer- based mathematical modeling environment for researchers in tracer kinetics, pharmacokinetics, enzyme kinetics, physiology, and other biological and nonbiological fields. Since its beginning, Kinetica has been designed to eventually bring together a range of modeling tools, including the design of optimal experiments, into a consistent, user-friendly, and intuitive program. The goal of the current research is to begin the specification, development, and implementation of experimental design tools to be incorporated into Kinetica. Specifically, the applicants will develop a prototype interface with which the user will define the experimental conditions to optimize, invoke constraints, select a design goal, initiate an analysis, and display and interpret results. Design goals available to the user will include parameter estimation, prediction, model discrimination, and any other goal identified during Phase I. Considerable effort will go into exhaustively considering all combinations of available experimental features, then identifying and prioritizing those for which the required theory or computational tools are not available. Theory will be developed as needed and in Phase II, the numerical methods with highest priorities will be implemented, producing a fully functional program. Creation and usability testing of the interface and rigorous definition of the computational requirements will demonstrate the feasibility of the software.